Globular cluster Messier
30 covers a distance of about 90 light years across, and appears to us under an
angular diameter of about 12.0 arc minutes. It is fairly dense (as its
concentration class V indicates), and a fine object in even small telescopes.
Its brightest red giant stars are about of apparent visual magnitude 12.1, its
horizontal branch giants at magnitude 15.1.The
core of M30 exhibits an extremely dense stellar population, and has undergone a
core collapse, similar to at least 20 other of the 150 globulars in the Milky
Way Galaxy, including M15, M70, and possibly M62.

M30 was one of the
original discoveries of Charles Messier, who catalogued it on August 3, 1764 and
like most of his globulars, described it as round nebula, containing no stars.
It was first resolved by William Herschel around 1784. (*)

At the right of M30 we
have 41 Capricorni shining in magnitude 5.25. The star is a good reference for
observes to find M30 since it is only at 22 arc minutes.